English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.We address the controversial issue of the structural stability of Li 7La3Zr2O12 garnets, focusing on the mechanisms that result in the transformation from tetragonal to cubic symmetry. We show that undoped tetragonal Li7La3Zr2O 12 not exposed to humidity at any moment undergoes a reversible phase transition to cubic symmetry at Tc ≃ 645 °C that we ascribe to lithium dynamic effects. On the other hand, a close correlation has been found between the appearance of a cubic phase between 100 and 200 °C in X-ray diffractograms and the presence of water, either in the atmosphere in which experiments are performed or already in the starting material. The natures of the high and low-temperature cubic garnets are totally different: the one found above the phase transition does not involve any change in the stoichiometry, whereas the cubic phase formed at low temperature is a hydrated, lithium defective phase, due to the combined effect of water insertion into the garnet structure and the H+/Li+ exchange mechanism. Differences in the actual compositions of the samples depending on their thermal history are corroborated by TG-MS experiments. Chemical reactions and phases formed along the thermal evolution are elucidated with the help of Raman spectroscopy. © 2013 The Royal Society of Chemistry.This work has been supported by the Spanish Ministerio de Economía and Feder funds through grant MAT2010-19837-C06-06. A. Orera acknowledges the financial support provided by CSIC and ESF through a JAE-Doc contract. G. Larraz acknowledges the financial support provided by Gobierno de Aragón through a PhD grant (B108/11).The authors also thank the Unit of Information Resources for Research (URICI-CSIC) for the co-financing of this publication in Open Access.Peer Reviewe

Cubic phases of garnet-type Li7La3Zr2O12: the role of hydration